This systematic review examined the measurement properties of the 6-min walk test (6MWT), incremental shuttle walk test (ISWT) and endurance shuttle walk test (ESWT) in adults with chronic respiratory disease.Studies that report the evaluation or use of the 6MWT, ISWT or ESWT were included. We searched electronic databases for studies published between January 2000 and September 2013.The 6-min walking distance (6MWD) is a reliable measure (intra-class correlation coefficients ranged from 0.82 to 0.99 in seven studies). There is a learning effect, with greater distance walked on the second test (pooled mean improvement of 26 m in 13 studies). Reliability was similar for ISWT and ESWT, with a learning effect also evident for ISWT (pooled mean improvement of 20 m in six studies). The 6MWD correlates more strongly with peak work capacity (r50.59-0.93) and physical activity (r50.40-0.85) than with respiratory function (r50.10-0.59). Methodological factors affecting 6MWD include track length, encouragement, supplemental oxygen and walking aids. Supplemental oxygen also affects ISWT and ESWT performance. Responsiveness was moderate to high for all tests, with greater responsiveness to interventions that included exercise training.The findings of this review demonstrate that the 6MWT, ISWT and ESWT are robust tests of functional exercise capacity in adults with chronic respiratory disease.
OverviewThe aim of this systematic review was to examine the measurement properties for the 6-min walk test (6MWT), incremental shuttle walk test (ISWT) and endurance shuttle walk test (ESWT) in adults with chronic respiratory disease. A companion paper describes the standard operating procedures for the tests [1]. The key findings of this systematic review are as follows.1) The 6-min walking distance (6MWD) is a valid and reliable measure of exercise capacity for people with chronic lung disease. The 6MWD correlates more strongly with measures of peak work capacity and physical activity than with respiratory function or quality of life, which supports its conceptualisation as a test of functional exercise performance.2) The ISWT offers a different protocol to the 6MWT as it is incremental and externally paced. The ISWT is a valid and reliable measure of cardiopulmonary exercise capacity in chronic obstructive pulmonary disease (COPD), where there is a strong relationship between ISWT distance and peak oxygen uptake (V9O 2 peak) or work rate on a cardiopulmonary exercise test (CPET).3) A learning effect is observed for the 6MWT and the ISWT. The second test usually is the better compared with the first, but this is inconsistent.4) The ESWT is a test of endurance capacity. It is externally paced and is performed along the same course as the ISWT. Two tests do not appear to be necessary if the second test is conducted on the same day.5) Reference equations have been proposed for the 6MWD and the ISWT. Age, height and weight are included in most equations. The influence of race and ethnicity is unclear.6) The safety profile of ...